Prickly Pear Fruit and Cladodes

Abstract

INTRODUCTION The prickly pear cactus plant belongs to the family Cactaceae, subfamily Opuntioideae, and is a xetrophyte producing about 200–300 species, mainly growing in arid (less than 250 mm annual precipitation) and semi-arid (250–450 mm annual precipitation) zones. The crop is produced and consumed in several countries. It is native to North America, and densely produced in the desert zones of the southern United States, north-central Mexico and Peru. From there it has been taken to several other parts of the world including Africa and Europe. The plants thrive well in subtropical, semi-arid climates. It is adapted to grow and produce under low water regimes and poor soils (Nobel 1994). As a CAM (crassulacean acid metabolism) plant, Opuntia spp. is characterized by high water use efficiency of 4–10 mmol CO 2 per mol H 2 O compared to C 3 – and C 4 – plants, with efficiencies of 1.0–1.5 mmol and 2–3 mmol CO 2 per mol H 2 O, respectively. It exhibits the highest production rate in terms of above-ground biomass of all known crop plants, and the biomass production was found to increase upon the increase in atmospheric CO 2 concentrations (thus counter-acting the greenhouse effect) (Nobel 1991; Nobel & Israel 1994; Goldstein et al. 1991). Because of its high adaptability and multiple uses, it has been dispersed from its native habitats in North America to other regions in the world (Barbera 1995). Cactus fruit and cladodes (Figures 13.1 and 13.2) can be readily and abundantly produced under high temperature and little water, conditions unfavourable for the production of many other crops. Cactus plants serve numerous purposes; such as sources for fruit and vegetables, for medicinal and cosmetic purposes, as forage, for building materials, as source for natural colours. However, many of these uses are still very restricted to a very few countries, and in light of global desertification and declining water sources, Opuntia spp. is gaining importance as an effective source of food including as vegetable (Flores 1995). Internationally, about 100 000 ha are devoted to Opuntia fruit and cladode commercial production; however, more than 3 million hectares of Opuntias are grown in native habitats (Barbera 1995). In Mexico over 50 000 ha of prickly pear cactus are cultivated commercially, of which over 10 000 ha are devoted to the production of cladodes, with an annual production of about 600 000 metric tons per annum. Mexico is the only country planting cladodes for commercial use as a vegetable. Opuntia ficus-indica is cultivated in more than 20 countries (Nobel 1988). Nopalea cochenillifera is primarily cultivated in southern California and Texas, and the cladodes of this species are softer, devoid of spines, contain less mucilage, and are greener than those of Opuntia spp. (Mizrahi et al. 1997). The Opuntia ficusindica (L.) Mill. species has gradually attained economic importance in Sicilian agriculture (Galati et al. 2002). Similarly its importance has grown in northern Mexico (Borrego-Escalante et al. 1990), the Mediterranean basin (Le Houerou 1996a), the arid highlands of western Asia (Le Houerou 1996b) and the south-western United States (Parish & Felker, 1997). Cold hardiness of Opuntia spp. clones used for fruit, forage or vegetable production have been reported by Le Houerou (1971), Russell and Felker (1987), Guevara et al. (1999, 2000), Gregory et al. (1993)